3GPP (3rd Generation Partnership Project) is a standardization project that studies and establishes the specifications for a cellular mobile communication system based on a network that develops GSM (Global System for Mobile Communications) and W-CDMA (Wideband-Code Division Multiple Access). In 3GPP, W-CDMA has been standardized as the 3rd generation cellular mobile communication system, and is successively being put into service. HSPA (High-Speed Packet Access), which is a further improvement in communication speed, has also been standardized, and is beginning to come into service. 3GPP is studying EUTRA (Evolved Universal Terrestrial Radio Access), which is an evolved third-generation wireless access technology, and Release 8 of the specifications was completed at the end of 2008. Additionally, a study of Advanced EUTRA (also referred to as LTE-Advanced or LTE-A), which is an extension of EUTRA, is progressing (Non-Patent Document 1).
In LTE-A, carrier aggregation (referred to hereinafter as CA) has been proposed as a technology for enabling high-speed data transfer equivalent to or exceeding IMT-Advanced while maintaining compatibility with EUTRA. CA technology is technology whereby a mobile station apparatus simultaneously receives signals using multiple downlink component carriers (hereinafter, referred as CCs; for example, a 20-MHz bandwidth) having either contiguous or non-contiguous frequency bands, so as to emulate the formation of a carrier signal with a broadband frequency bandwidth (for example, 100 MHz using five CCs) and achieve high-speed downlink data transfer. In the same manner, using CA technology, the base station apparatus simultaneously receives multiple uplink contiguous or non-contiguous CCs (having, for example, a bandwidth of 20 MHz) from a mobile station apparatus, so as to emulate the formation of a carrier signal having a broadband frequency bandwidth (for example 40 MHz with two CCs) and achieve high-speed uplink data transfer.
<The Relationship Between the Adoption of CA Technology and Combination of Mobile Station Apparatus Configurations>
The combination of CCs in CA technology is dependent upon diverse variables, such as the overall number of uplink CCs (for example, two), the overall number of downlink CCs (for example, five), the number of frequency bands (for example, three) (for example, 700-MHz band, 2-GHz band, 3-GHz band, or the like), contiguous or non-contiguous CCs, and the transfer mode (for example, FDD, TDD).
FIG. 39 is a simplified drawing that shows a combination of CCs in the conventional art. In this drawing, the horizontal axis indicates frequency. This drawing also shows the case of two frequency bands, frequency band 1 (2-GHz band) and frequency band 2 (3-GHz band). What is shown in this drawing are the six cases divided vertically, of which cases 1 to 3 show the case of the FDD (frequency division duplex) transmission mode and the cases 4 to 6 shows the TDD (time division duplex) transmission mode.
Case 1 in FIG. 39 shows the combination of CCs if three contiguous CCs (center frequencies of f1_R1, f1_R2, and f1_R3) are selected within the band 12 (downlink) and two contiguous CCs (center frequencies of f1_T1 and f1_T2) are selected within the band 11 (uplink) in the same frequency band 1.
Case 2 shows the combination of CCs if two non-contiguous CCs (center frequencies of f1_R1 and f1_R3, the Intra CA case) are selected within the band 12 and two non-contiguous CCs (center frequencies of f1_T1 and f1_T3) are selected within the band 11 in the same frequency band 1.
Case 3 shows the combination of CCs if a CC (center frequency of f1_R1) is selected within the band 12 in the frequency band 1, a CC (center frequency of f2_R1) is selected within band 22 in the frequency band 2, and a CC (center frequency of f1_T1) is selected in band 1 in the frequency band 1. The case 3 shows two non-contiguous CCs (the Inter CA case) selected in different frequency bands 1 and 2 for downlink communication, and one CC selected for downlink communication.
Cases 4, 5, and 6 each correspond to the cases 1, 2, and 3. For example, in the case 4, the combination of CCs shown is for the case using band 12 in downlink and uplink communication, and selecting the CCs depending on the time slot. The case 4 shows the combination of CCs in the case of selecting three contiguous CCs (center frequencies of f1_1, f1_2, and f1_3) in band 12 for downlink communication, and selecting two contiguous CCs (center frequencies of f1_1 and f1_2) for uplink communication.
For non-contiguous CCs in the same frequency band (for example, those having center frequencies of f1_R1 and f1_R3 in FIG. 39), there is the case in which multiple base station apparatuses transmit a transmitted signal in synchronization with a frame or the like (referred to as synchronization between base stations), the case of an asynchronous condition in which each base station transmits a transmitted signal independently, and the case in which, although synchronization is done between base stations, for example, propagation path delay occurs, so that the frame timing of the OFDM (orthogonal frequency division multiplexing) signal is offset, causing an asynchronous condition.
With regard to communication using a base station apparatus with contiguous CCs in the same frequency band (for example, center frequencies of f1_R1 and f1_R2), various technologies have been proposed in consideration of elements such as backward compatibility with LTE systems, the 100-kHz UMTS (Universal Mobile Telecommunications System) wireless channel raster, guard bands between CCs, guard bands at both ends of contiguous CCs, and frequency utilization efficiency and the like (for example, Non-Patent Document 1). With contiguous CCs, however, it is necessary to have a separate baseband processing circuit in the transmitting and receiving circuit to maintain compatibility with LTE systems because the guard bands between CCs are not integral multiples of the 15-kHz subcarrier bandwidth.
In order to accommodate the various cases noted above, the constitution of the mobile station apparatus is dependent upon such things as: (a) the number of frequency bands; (b) the total number of uplink and downlink CCs; (c) contiguous or non-contiguous CCs (Intra CA or Inter CA); (d) the wireless transmission mode; (e) synchronous or asynchronous between downlink CCs or between base station apparatuses; (f) various CC bandwidths (for example, 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz); and (g) the bandwidth (for example, 100 MHz) of multiple contiguous CCs having an OFDM subcarrier bandwidth of 15 MHz (for example, Non-Patent Documents 2 and 3).
<The Relationship Between the Adoption of Other Technologies in LTE-A and Combination of Mobile Station Apparatus Configurations>
The conditions required by LTE-A (Non-Patent Document 4) for the case in which a mobile station apparatus is moving at high speed in the case of a 100-Mbps downlink and a 75-Mbps uplink, are a data transfer rate of 1000 Mbps for the downlink and of 500 Mbps for the uplink. To achieve this, other than adopting CA technology, technology for achieving high-order MIMO will be adopted. For example, with 8×8 MIMO (in which there are eight base station apparatus transmitting antennas, eight mobile station apparatus receiving antennas, the number of MIMO streams or the number of ranks being referred to hereafter as a rank of 8) for the downlink, a data transfer rate of 1000 Mbps is achieved with a 100-MHz transmission bandwidth. With 4×4 MIMO (hereinafter referred to as the number of MIMO streams or the number of ranks of 4) for the uplink, a 600-Mbps data transfer rate is achieved with a 40-MHz transmission bandwidth. Also, to expand the cell edge data transfer rate and the cell coverage area, technology for coordinated communication (CoMP: coordinated multipoint) between base station apparatuses and technology for uplink transmitting diversity are introduced.
The constitution of the mobile station apparatus is, therefore, dependent upon (h) the downlink and uplink MIMO system, (i) the coordinated communication CoMP between base stations, and (j) the uplink transmitting diversity system and the like.
<The Relationship Between the Carrier Operating Condition and the Combination of Mobile Station Apparatus Configurations>
Frequency allocations with respect to IMT-Advanced were determined at the 2007 World Radiocommunication Conference WRC-07. However, the current IMT bands (Non-Patent Documents 4 and 5) are not all bands common to all countries, each mobile telephone service operator operating under the frequency allocation of its own country. Depending upon the frequency allocation situation in each country, the mobile telephone service operators use different transmission modes (TDD and FDD). Blending of the different transmission modes (for example, mixed coexistence of different transmission modes between macrocells and microcells, indoor and outdoor areas, and at proximity to and at the edge of cells) has been proposed.
LTE-A mobile telephone service operators, for example as described in Non-Patent Document 5, can select from the EUTRA system frequency band numbers 1 to 41 (E-UTRA operating band numbers; hereinafter referred to a frequency band numbers) that are indicated by the EUTRA system frequency bands (E-UTRA operating bands). Also, for example, each of the mobile telephone service operators participating in the 3GPP standards organization have been studying various frequency operation priority scenarios (deployment scenarios with the highest priority for the feasibility study). Additionally, for example, US mobile telephone service operators have been proposing frequency operating priority scenarios (US cellular bandwidth aggregation scenarios).
Therefore, considering (k) the frequency allocation situation of each mobile telephone service operator and (l) domestic and overseas roaming, the configuration of the mobile station apparatus becomes even more complex (Non-Patent Documents 6, 7, and 8).
The above-noted elements (a) to (l) (referred to as LTE-A technical elements) did not greatly influence the constitution of mobile station apparatuses in past mobile communication systems. For example, as shown in FIG. 19, in the LTE-A system, it was possible to define the category of the mobile station apparatus (UETRA category, five types existing) by the buffer size of the mobile station apparatus data processing software (downlink maximum data rate of 10 Mbps to 300 Mbps) and the maximum MIMO constitution (1×1, 2×2, 4×4). Once the category is determined, the constitution of the mobile station apparatus can be established. Stated differently, it is sufficient to provide the mobile telephone service operators with five types of mobile station apparatuses or to distribute five types of mobile station apparatuses into the market.